The present invention relates to a dual-mass flywheel for the drive train of an automotive vehicle.
A dual-mass flywheel for the drive train of an automotive vehicle, which is described and shown in DE-A-39 09 892, has a primary mass that is adapted to be fastened concentrically with the axis of rotation to a crankshaft of the internal-combustion engine of the automotive vehicle and a secondary mass which is mounted for rotation around the axis of rotation relative to the primary mass. The secondary mass is attached to a friction clutch located in the drive train between the internal-combustion engine and a gear box of the automotive vehicle. The secondary mass is coupled in a rotationally elastic manner with the primary mass by a torsion-damping arrangement.
The primary mass of the previously known dual-mass flywheel is made up essentially of two formed sheet-metal parts. A first part has the shape of a pan and includes a base wall portion that lies essentially radially and is attached to the crankshaft and a peripheral flange portion, which is joined to the perimeter of the base portion and extends in an essentially axial direction away from the crankshaft. The second formed sheet-metal part of the dual mass flywheel forms a wall that extends in an essentially radial direction and is attached at its perimeter to the flange portion of the first part. Together, the two formed sheet-metal parts define a cavity which is concentric with the axis of rotation and is located in a radially outer region of the primary mass. The cavity receives the springs of the torsion-spring arrangement.
In such a dual-mass flywheel, the primary mass has a comparatively complicated shape, inasmuch as it accommodates the torsion-damping arrangement in the cavity. If formed sheet-metal parts are used, the desired shape can be produced in a sufficiently practical manner. It has been found, however, that the flywheel mass of a primary mass made up of sheet-metal parts is too low for many applications. Consequently, consideration could be given to using thicker sheet-metal for the formed sheet-metal parts; however, on the one hand, this complicates manufacture, and on the other hand, it becomes impractical for reasons of space, in particular because accommodation of the springs of the torsion-damping arrangement requires a certain amount of assembly space.